<template>
  <div id="app">
    <div>
      <span>姓名:</span>
      <input type="text" v-model.trim="form.uname" />
    </div>
    <div>
      <span>年龄:</span>
      <input type="number" v-model.number="form.age" />
    </div>
    <div>
      <span>性别:</span>
      <select v-model="form.gender">
        <option value="男">男</option>
        <option value="女">女</option>
      </select>
    </div>
    <div>
      <button @click="changeList">添加/修改</button>
    </div>
    <div>
      <table border="1" cellpadding="10" cellspacing="0">
        <tr>
          <th>序号</th>
          <th>姓名</th>
          <th>年龄</th>
          <th>性别</th>
          <th>操作</th>
        </tr>
        <tr v-for="(item, index) in list" :key="item.id">
          <td>{{ index + 1 }}</td>
          <td>{{ item.uname }}</td>
          <td>{{ item.age }}</td>
          <td>{{ item.gender }}</td>
          <td>
            <button @click="del(item.id)">删除</button>
            <button @click="edit(item.id)">编辑</button>
          </td>
        </tr>
      </table>
    </div>
  </div>
</template>
<script>
export default {
  data() {
    return {
      list: JSON.parse(localStorage.getItem('students-list')) || [],
      form: {
        id: '',
        uname: '',
        age: '',
        gender: '',
      },
    }
  },
  methods: {
    // 添加/修改 操作 operate
    changeList() {
      // 判断输入数据不能为空 如果为空则提醒
      if (!this.form.uname || this.form.age === '' || this.form.age < 0 || this.form.gender === '') {
        alert('请正确输入信息')
        return
      } 
      // 判断输入框数据有没有 this.form.id ，没有就是添加操作 push 进行渲染
      if (!this.form.id) {
        this.list.push({
          id: this.list.length ? this.list.at(-1).id + 1 : 1,
          uname: this.form.uname,
          age: this.form.age,
          gender: this.form.gender,
        })
      }else {
        // 如果携带id 就是编辑修改操作 遍历数组找到id那一项 重新赋值 splice 替换渲染
        this.list.filter((item, index) => {
        if (item.id === this.form.id) {
          item = {...this.form}
        }
        this.list.splice(index, 1, item)
      })
      }
       this.form.id = ''
       this.form.uname = ''
       this.form.age = 0,
       this.form.gender = ''
    },
    del(id) {
      this.list = this.list.filter((item) => item.id !== id)
    },
    edit(id) {
      // console.log(id)
      this.list.filter((item, index) => {
        if (item.id === id) {
          this.form = { ...item }
        }
      })
    },
  },
  watch: {
    list() {
      localStorage.setItem('students-list', JSON.stringify(this.list))
    },
  },
}
</script>